docs: def node_iterator(self):
          """Provides an iterator over the nodes.
  
          """
          return iter(self._node_attributes)
  
  	def has_hypernode(self, hypernode):
          """Determines if a specific hypernode is present in the hypergraph.
  
          :param node: reference to hypernode whose presence is being checked.
          :returns: bool -- true iff the node exists in the hypergraph.
  
          """
          return hypernode in self._hypernode_attributes